The women of original series Star Trek occasionally played crucial roles in the ship’s functioning or in the progress of an episode’s narrative, but mostly they were like everyone else on Star Trek  focused on the actions and well-being of the Enterprise and of the three major protagonists at the heart of her crew: Kirk, Spock, and McCoy. Women weren’t present in Star Trek to reveal something about themselves. They were present to reveal something about humanity, the five-year mission, and the men who were the driving force behind it. And they were never more revealing than when they used to date one of those men. In the first season of ST:TOS, the series introduced viewers to figures from each of the trio’s romantic past.

McCoy’s ex, Nancy Crater, appeared in “The Man Trap.” Following her failed relationship with Bones, she married an archaeologist and moved to a remote asteroid as a trailing spouse. Bones is a sentimental old Southern boy, and still carries a torch for her. Unfortunately for him, Nancy died a few years back and has been replaced by a shape-shifting salt vampire. Bones is such a romantic that he doesn’t notice. While redshirts are dropping dead for mysterious reasons (but only around Nancy), and the rest of the crew is noticing a series of puzzling discrepancies between the doctor’s descriptions of Nancy and the way she appears to them, Bones is thrilled to be (platonically) re-united with his lost love. He can’t figure out why she and her husband are so resistant to routine physicals, or why they keep saying they’d like to be left alone with some salt tablets. He doesn’t see the truth until she attacks him. He kills her to save the crew.

The message: Space exploration comes at a high price. If it would bother you to kill what appears to be your ex-girlfriend but is actually the last of its homicidally salt-thirsty kind, you might be happier staying home.

What we’ve learned about McCoy: He might be happier staying home. This episode helps explain his cynicism about things like brick-laying and transporters. However, in an important sense, the Enterprise is his home. Nancy represents McCoy’s personal ties to things that lie outside the Enterprise, and by the time the episode is over she’s died twice. Everything that’s left for McCoy now is flying through space with him.

Everyone knows Spock has an ex-girlfriend. His attempt to be re-united with her in the second season episode “Amok Time” was an epic failure told in an epic story, which, bizarrely, was immortalized in an epic commemorative Hallmark holiday ornament in 2010. Spock’s season one ex-girlfriend appeared in “This Side of Paradise.” She is less memorable than T’Pring, but equally important to understanding Spock. Leila Kalomi is a botanist, who knew and loved Spock years ago. Although half-human, Spock’s Vulcan nature prevented him from returning her love. This one-sided relationship ended, and Leila relocated to Omicron Ceti III to live on a colony bombarded by deadly Berthold rays. The cosmic radiation dissolved all the colony’s cows, but the colonists survived thanks to some protective and totally cool plant spores. They’ve become peace-loving vegetarians. Inhaling the spores unleashes the human side of Spock’s nature, and he’s thrilled to discover that, as a result, he can love Leila. But the crew is deserting, and Kirk needs Spock’s help. Kirk brings Spock down from his high by making him angry, and together they build a sonic transmitter to neutralize the spores’ effect on the rest of the crew. Spock meets with Leila one last time and she realizes he will never love her again. In a beautiful, subtle moment, Leila asks Spock why he never told her he had a given name, and he tells her that she couldn’t pronounce it.

The message: Even half-Vulcans can get beer goggles.

What we’ve learned about Spock: His ears, his green blood, and his stoicism alienate him, but deep down inside Spock there is something much deeper that makes him profoundly alien.

Given Kirk’s reputation for womanizing, the major surprise of the first season is that he encounters so few of his ex-girlfriends. His on-going romantic attachments are major issues in several episodes. By the time we see Kirk have a conversation with an ex, we’ve seen him wrestle with his both his feelings and Yeoman Rand (“The Naked Time” and “The Enemy Within”), deal with the fall-out from an incident with a tipsy psychiatrist at the Science Department Christmas party (“Dagger of the Mind”), and use a case of Number Two pencils to fend off a besotted tween (“Miri”). His most notable first season ex is Areel Shaw, an Academy classmate who serves as lawyer for the prosecution when Kirk is accused of murder in “Court Martial.” Areel presents a solid case against Kirk, pointing out major discrepancies between his testimony and the Enterprise‘s records. Kirk is forced to fight for his career against inaccurate computer records that turn out to have been manipulated by an officer with a vendetta. His honesty, his honor, and his memory are all called into question. But Areel is only tough in the courtroom. She reveals the prosecution’s strategy, helps Kirk find a lawyer, and kisses Kirk passionately after he is acquitted.

The message: Everyone loves Kirk.

What we’ve learned about Kirk: He really relies on that.

Ellen Cheeseman-Meyer has been a Star Trek fan since the early 90s, but only started watching episodes in 2009. She teaches history and reads a lot.